耐万古霉素金黄色葡萄球菌生物学特性改变与细菌鉴定

目的 了解金黄色葡萄球菌对万古霉素耐药后生物学特性的变化及其对临床细菌鉴定结果的影响。方法 使用万古霉素体外诱导试验将1株临床分离的异质性万古霉素耐药金黄色葡萄球菌（h-VRSA）逐渐诱导为万古霉素中介耐药金黄色葡萄球菌（VISA），观察原代菌和诱导菌的生长特征和生化反应，并使用VITEK32和MicroscanWalkAway40进行细菌鉴定。结果 h-VRSA和VISA的主要生物学特性改变为：菌落大小不等、色素由淡黄色变成灰白色、溶血环消失，血浆凝固酶、甘露醇、甘露糖等生化反应由阳性转为阴性；对杆菌肽由敏感变为耐药；仪器鉴定结果为溶血葡萄球菌或模仿葡萄球菌。结论 金黄色葡萄球菌对万古霉素耐药后可表现出培养特征、生化反应等一系列表型特征的改变，并可导致临床细菌鉴定结果错误。

The Biological Characteristic and Identification of Staphylococcus Aureus of Resistance to Vancomycin

Objective To know the change of biological characteristic of S.aureus of resistance to vancomycin and its influence on the identification of species. Methods A hetero-vancomycin-resistance S. aureus (h-VRSA) strain isolated from clinical specimen was gradually induced to vancomycin-intermediate S.aureus (VISA) by vancomycin in vitro. The phenotypic characteristic was detected and the strains were identified by Vitek32 and WalkAway40 instruments. Results Both h-VRSA and VISA demonstrated variable colony morphologies. The pigment of colonies changed from yellow-white to grey-white. The zone of beta-hemolysis became narrow or barely detectable. The slide coagulase test and production of acid from mannitol, mannose became negative. The susceptibility to bacitracin became resistance.The species of induced strains were identified as S. haemolyticus or S. simulans by instruments. Conclusion Both h-VRSA and VISA demonstrated variable culture characteristics and biochemical responds, which can result to the error species identification.